diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index 0e169d60d50..f2c89dcbe92 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -3907,21 +3907,8 @@ build
   </li>
 </ul>
 
-<h2>General OS setup</h2>
+<h2>Memory Management</h2>
 <ul>
-  <li>
-    <code>CONFIG_ARCH_LOWPUTC</code>: architecture supports low-level, boot
-    time console output
-  </li>
-  <li>
-    <code>CONFIG_NUTTX_KERNEL</code>:
-      With most MCUs, NuttX is built as a flat, single executable image
-      containing the NuttX RTOS along with all application code.
-      The RTOS code and the application run in the same address space and at the same kernel-mode privileges.
-      If this option is selected, NuttX will be built separately as a monolithic, kernel-mode module and the applications
-      can be added as a separately built, user-mode module.
-      In this a system call layer will be built to support the user- to kernel-mode interface to the RTOS.
-  </li>
   <li>
     <code>CONFIG_MM_REGIONS</code>: If the architecture includes multiple
     regions of memory to allocate from, this specifies the
@@ -3939,6 +3926,50 @@ build
     can be defined so that those MCUs will also benefit from the
     smaller, 16-bit-based allocation overhead.
   </li>
+  <li>
+    <code>CONFIG_HEAP2_BASE</code> and <code>CONFIG_HEAP2_SIZE</code>:
+      Some architectures use these settings to specify the size of
+      a second heap region.
+  <li>
+  </li>
+    <code>CONFIG_GRAN</code>:
+      Enable granual allocator support.  Allocations will be aligned to the
+      granule size; allocations will be in units of the granule size.
+      Larger granules will give better performance and less overhead but
+      more losses of memory due to alignment and quantization waste.
+      NOTE: The current implementation also restricts the maximum
+      allocation size to 32 granaules.  That restriction could be
+      eliminated with some additional coding effort.
+  <li>
+  </li>
+    <code>CONFIG_GRAN_SINGLE</code>:
+      Select if there is only one instance of the granule allocator (i.e.,
+      gran_initialize will be called only once. In this case, (1) there
+      are a few optimizations that can can be done and (2) the GRAN_HANDLE
+      is not needed.
+  </li>
+  <li>
+    <code>CONFIG_DEBUG_GRAM</code>:
+      Just like <code>CONFIG_DEBUG_MM</code>, but only generates ouput from the gran
+      allocation logic.
+  </li>
+</ul>
+
+<h2>General OS setup</h2>
+<ul>
+  <li>
+    <code>CONFIG_ARCH_LOWPUTC</code>: architecture supports low-level, boot
+    time console output
+  </li>
+  <li>
+    <code>CONFIG_NUTTX_KERNEL</code>:
+      With most MCUs, NuttX is built as a flat, single executable image
+      containing the NuttX RTOS along with all application code.
+      The RTOS code and the application run in the same address space and at the same kernel-mode privileges.
+      If this option is selected, NuttX will be built separately as a monolithic, kernel-mode module and the applications
+      can be added as a separately built, user-mode module.
+      In this a system call layer will be built to support the user- to kernel-mode interface to the RTOS.
+  </li>
   <li>
     <code>CONFIG_MSEC_PER_TICK</code>: The default system timer is 100Hz
     or <code>MSEC_PER_TICK</code>=10.  This setting may be defined to inform NuttX
diff --git a/configs/README.txt b/configs/README.txt
index b51b87bece7..b3d0e91f51d 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -270,8 +270,6 @@ defconfig -- This is a configuration file similar to the Linux
     CONFIG_DEBUG_GRAPHICS - enable NX graphics debug output
       (disabled by default)
 
-    CONFIG_ARCH_LOWPUTC - architecture supports low-level, boot
-      time console output
     CONFIG_MM_REGIONS - If the architecture includes multiple
       regions of memory to allocate from, this specifies the
       number of memory regions that the memory manager must
@@ -285,6 +283,28 @@ defconfig -- This is a configuration file similar to the Linux
       of size less than or equal to 64Kb.  In this case, CONFIG_MM_SMALL
       can be defined so that those MCUs will also benefit from the
       smaller, 16-bit-based allocation overhead.
+    CONFIG_HEAP2_BASE and CONFIG_HEAP2_SIZE
+      Some architectures use these settings to specify the size of
+      a second heap region.
+    CONFIG_GRAN
+      Enable granual allocator support.  Allocations will be aligned to the
+      granule size; allocations will be in units of the granule size.
+      Larger granules will give better performance and less overhead but
+      more losses of memory due to alignment and quantization waste.
+      NOTE: The current implementation also restricts the maximum
+      allocation size to 32 granaules.  That restriction could be
+      eliminated with some additional coding effort.
+    CONFIG_GRAN_SINGLE
+      Select if there is only one instance of the granule allocator (i.e.,
+      gran_initialize will be called only once. In this case, (1) there
+      are a few optimizations that can can be done and (2) the GRAN_HANDLE
+      is not needed.
+    CONFIG_DEBUG_GRAM
+      Just like CONFIG_DEBUG_MM, but only generates ouput from the gran
+      allocation logic.
+
+    CONFIG_ARCH_LOWPUTC - architecture supports low-level, boot
+      time console output
     CONFIG_MSEC_PER_TICK - The default system timer is 100Hz
       or MSEC_PER_TICK=10.  This setting may be defined to
       inform NuttX that the processor hardware is providing
diff --git a/configs/fire-stm32v2/nsh/defconfig b/configs/fire-stm32v2/nsh/defconfig
index ef5fcbf4008..fda34debe31 100644
--- a/configs/fire-stm32v2/nsh/defconfig
+++ b/configs/fire-stm32v2/nsh/defconfig
@@ -481,6 +481,7 @@ CONFIG_FAT_MAXFNAME=32
 #
 # CONFIG_MM_SMALL is not set
 CONFIG_MM_REGIONS=1
+# CONFIG_GRAN is not set
 
 #
 # Library Routines
diff --git a/configs/shenzhou/nsh/defconfig b/configs/shenzhou/nsh/defconfig
index 7aa442e12e8..0c18b129f2c 100644
--- a/configs/shenzhou/nsh/defconfig
+++ b/configs/shenzhou/nsh/defconfig
@@ -304,66 +304,22 @@ CONFIG_DEV_NULL=y
 # CONFIG_DEV_ZERO is not set
 # CONFIG_LOOP is not set
 # CONFIG_RAMDISK is not set
-
-#
-# CAN Driver Options
-#
 # CONFIG_CAN is not set
-
-#
-# PWM Driver Options
-#
 # CONFIG_PWM is not set
-
-#
-# I2C Driver Options
-#
 # CONFIG_I2C is not set
-
-#
-# SPI Driver Options
-#
 CONFIG_SPI=y
 # CONFIG_SPI_OWNBUS is not set
 CONFIG_SPI_EXCHANGE=y
 CONFIG_SPI_CMDDATA=y
-
-#
-# RTC Driver Options
-#
 CONFIG_RTC=y
 # CONFIG_RTC_DATETIME is not set
 # CONFIG_RTC_HIRES is not set
 # CONFIG_RTC_ALARM is not set
-
-#
-# Watchdog Driver Options
-#
 # CONFIG_WATCHDOG is not set
-
-#
-# Analog Driver Options
-#
 # CONFIG_ANALOG is not set
-
-#
-# Block-to-Character Driver Support
-#
 # CONFIG_BCH is not set
-
-#
-# Input device Driver Options
-#
 # CONFIG_INPUT is not set
-
-#
-# LCD Driver Options
-#
 # CONFIG_LCD is not set
-
-#
-# MMCSD Driver Options
-#
 CONFIG_MMCSD=y
 CONFIG_MMCSD_NSLOTS=1
 # CONFIG_MMCSD_READONLY is not set
@@ -373,42 +329,14 @@ CONFIG_MMCSD_HAVECARDDETECT=y
 CONFIG_MMCSD_SPI=y
 CONFIG_MMCSD_SPICLOCK=12500000
 # CONFIG_MMCSD_SDIO is not set
-
-#
-# I2C Driver Options
-#
 # CONFIG_MTD is not set
-
-#
-# Network Device Driver Options
-#
 # CONFIG_NETDEVICES is not set
 # CONFIG_NET_SLIP is not set
-
-#
-# Pipe Options
-#
 # CONFIG_PIPES is not set
-
-#
-# Power Management Options
-#
 # CONFIG_PM is not set
 # CONFIG_POWER is not set
-
-#
-# Sensor Driver Options
-#
 # CONFIG_SENSORS is not set
-
-#
-# Osmocom-bb Sercomm Driver Options
-#
 # CONFIG_SERCOMM_CONSOLE is not set
-
-#
-# Serial Driver Options
-#
 CONFIG_SERIAL=y
 # CONFIG_LOWLEVEL_CONSOLE is not set
 # CONFIG_16550_UART is not set
@@ -427,20 +355,8 @@ CONFIG_USART2_BAUD=115200
 CONFIG_USART2_BITS=8
 CONFIG_USART2_PARITY=0
 CONFIG_USART2_2STOP=0
-
-#
-# USB Device Driver Options
-#
 # CONFIG_USBDEV is not set
-
-#
-# USB Host Driver Options
-#
 # CONFIG_USBHOST is not set
-
-#
-# Wireless Device Driver Options
-#
 # CONFIG_WIRELESS is not set
 
 #
@@ -496,6 +412,7 @@ CONFIG_FAT_LCNAMES=y
 CONFIG_FAT_LFN=y
 CONFIG_FAT_MAXFNAME=32
 # CONFIG_FS_FATTIME is not set
+# CONFIG_FAT_DMAMEMORY is not set
 # CONFIG_FS_RAMMAP is not set
 # CONFIG_NFS is not set
 # CONFIG_FS_NXFFS is not set
@@ -511,6 +428,7 @@ CONFIG_FAT_MAXFNAME=32
 #
 # CONFIG_MM_SMALL is not set
 CONFIG_MM_REGIONS=1
+# CONFIG_GRAN is not set
 
 #
 # Library Routines
diff --git a/drivers/net/enc28j60.c b/drivers/net/enc28j60.c
index eee9ff6f05b..a2f3d587159 100644
--- a/drivers/net/enc28j60.c
+++ b/drivers/net/enc28j60.c
@@ -164,6 +164,15 @@
  * Private Types
  ****************************************************************************/
 
+/* The state of the interface */
+
+enum enc_state_e
+{
+  ENCSTATE_UNIT = 0,                  /* The interface is in an unknown state */
+  ENCSTATE_DOWN,                      /* The interface is down */
+  ENCSTATE_UP                         /* The interface is up */
+};
+
 /* The enc_driver_s encapsulates all state information for a single hardware
  * interface
  */
@@ -172,7 +181,7 @@ struct enc_driver_s
 {
   /* Device control */
 
-  bool                  bifup;         /* true:ifup false:ifdown */
+  uint8_t               ifstate;       /* Interface state:  See ENCSTATE_* */
   uint8_t               bank;          /* Currently selected bank */
   uint16_t              nextpkt;       /* Next packet address */
   FAR const struct enc_lower_s *lower; /* Low-level MCU-specific support */
@@ -1656,7 +1665,7 @@ static int enc_ifup(struct uip_driver_s *dev)
        * controller
        */
 
-      priv->bifup = true;
+      priv->ifstate = ENCSTATE_UP;
       priv->lower->enable(priv->lower);
     }
 
@@ -1686,8 +1695,8 @@ static int enc_ifdown(struct uip_driver_s *dev)
   int ret;
 
   nlldbg("Taking down: %d.%d.%d.%d\n",
-       dev->d_ipaddr & 0xff, (dev->d_ipaddr >> 8) & 0xff,
-       (dev->d_ipaddr >> 16) & 0xff, dev->d_ipaddr >> 24 );
+         dev->d_ipaddr & 0xff, (dev->d_ipaddr >> 8) & 0xff,
+         (dev->d_ipaddr >> 16) & 0xff, dev->d_ipaddr >> 24 );
 
   /* Disable the Ethernet interrupt */
 
@@ -1704,7 +1713,7 @@ static int enc_ifdown(struct uip_driver_s *dev)
   ret = enc_reset(priv);
   enc_pwrsave(priv);
 
-  priv->bifup = false;
+  priv->ifstate = ENCSTATE_DOWN;
   irqrestore(flags);
   return ret;
 }
@@ -1737,7 +1746,7 @@ static int enc_txavail(struct uip_driver_s *dev)
 
   /* Ignore the notification if the interface is not yet up */
 
-  if (priv->bifup)
+  if (priv->ifstate == ENCSTATE_UP)
     {
       /* Check if the hardware is ready to send another packet.  The driver
        * starts a transmission process by setting ECON1.TXRTS. When the packet is
@@ -2131,8 +2140,7 @@ static int enc_reset(FAR struct enc_driver_s *priv)
 int enc_initialize(FAR struct spi_dev_s *spi,
                    FAR const struct enc_lower_s *lower, unsigned int devno)
 {
-  FAR struct enc_driver_s *priv ;
-  int ret;
+  FAR struct enc_driver_s *priv;
 
   DEBUGASSERT(devno < CONFIG_ENC28J60_NINTERFACES);
   priv = &g_enc28j60[devno];
@@ -2156,29 +2164,28 @@ int enc_initialize(FAR struct spi_dev_s *spi,
   priv->spi          = spi;           /* Save the SPI instance */
   priv->lower        = lower;         /* Save the low-level MCU interface */
 
-  /* Make sure that the interface is in the down state.  NOTE:  The MAC
-   * address will not be set up until ifup.  That gives the app time to set
-   * the MAC address before bringing the interface up.
+  /* The interface should be in the down state.  However, this function is called
+   * too early in initalization to perform the ENC28J60 reset in enc_ifdown.  We
+   * are depending upon the fact that the application level logic will call enc_ifdown
+   * later to reset the ENC28J60.  NOTE:  The MAC address will not be set up until
+   * enc_ifup() is called. That gives the app time to set the MAC address before
+   * bringing the interface up.
    */
 
-  ret = enc_ifdown(&priv->dev);
-  if (ret == OK)
+  priv->ifstate = ENCSTATE_UNIT;
+
+  /* Attach the interrupt to the driver (but don't enable it yet) */
+
+  if (lower->attach(lower, enc_interrupt))
     {
-      /* Attach the interrupt to the driver (but don't enable it yet) */
+      /* We could not attach the ISR to the interrupt */
 
-      if (lower->attach(lower, enc_interrupt))
-        {
-          /* We could not attach the ISR to the interrupt */
-
-          ret =  -EAGAIN;
-        }
-
-      /* Register the device with the OS so that socket IOCTLs can be performed */
-
-      (void)netdev_register(&priv->dev);
+      return -EAGAIN;
     }
 
-  return ret;
+  /* Register the device with the OS so that socket IOCTLs can be performed */
+
+  return netdev_register(&priv->dev);
 }
 
 /****************************************************************************
diff --git a/include/nuttx/gran.h b/include/nuttx/gran.h
index 2036a29a159..bb08f9b3740 100644
--- a/include/nuttx/gran.h
+++ b/include/nuttx/gran.h
@@ -43,6 +43,11 @@
 
 #include <nuttx/config.h>
 
+#include <sys/types.h>
+#include <stdint.h>
+
+#ifdef CONFIG_GRAN
+
 /****************************************************************************
  * Pre-Processor Definitions
  ****************************************************************************/
@@ -52,6 +57,8 @@
  *   granule allocator (i.e., gran_initialize will be called only once.
  *   In this case, (1) there are a few optimizations that can can be done
  *   and (2) the GRAN_HANDLE is not needed.
+ * CONFIG_DEBUG_GRAN - Just like CONFIG_DEBUG_MM, but only generates ouput
+ *   from the gran allocation logic.
  */
 
 /****************************************************************************
@@ -158,4 +165,5 @@ EXTERN void gran_free(GRAN_HANDLE handle, FAR void *memory, size_t size);
 }
 #endif
 
+#endif /* CONFIG_GRAN */
 #endif /* __INCLUDE_NUTTX_GRAN_H */
diff --git a/mm/Kconfig b/mm/Kconfig
index bf3540138f4..2e5bc95db8f 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -42,3 +42,33 @@ config HEAP2_SIZE
 	---help---
 		The size of the second heap region.
 
+config GRAN
+	bool "Enable Granule Allocator"
+	default n
+	---help---
+		Enable granual allocator support.  Allocations will be aligned to the
+		granule size; allocations will be in units of the granule size.
+		Larger granules will give better performance and less overhead but
+		more losses of memory due to alignment and quantization waste.
+
+		NOTE: The current implementation also restricts the maximum
+		allocation size to 32 granaules.  That restriction could be
+		eliminated with some additional coding effort.
+
+config GRAN_SINGLE
+	bool "Single Granule Allocator"
+	default n
+	depends on GRAN
+	---help---
+		Select if there is only one instance of the granule allocator (i.e.,
+		gran_initialize will be called only once. In this case, (1) there
+		are a few optimizations that can can be done and (2) the GRAN_HANDLE
+		is not needed.
+
+config DEBUG_GRAN
+	bool "Granule Allocator Debug"
+	default n
+	depends on GRAN && DEBUG
+	---help---
+		Just like CONFIG_DEBUG_MM, but only generates ouput from the gran
+		allocation logic.
diff --git a/mm/Makefile b/mm/Makefile
index 7e6eb68a75b..ef168f0db13 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -36,10 +36,15 @@
 -include $(TOPDIR)/Make.defs
 
 ASRCS	= 
-AOBJS	= $(ASRCS:.S=$(OBJEXT))
 CSRCS	= mm_initialize.c mm_sem.c  mm_addfreechunk.c mm_size2ndx.c mm_shrinkchunk.c \
 	  mm_malloc.c mm_zalloc.c mm_calloc.c mm_realloc.c \
 	  mm_memalign.c mm_free.c mm_mallinfo.c
+
+ifeq ($(CONFIG_GRAN),y)
+CSRCS	= mm_graninit.c mm_granalloc.c mm_granfree.c
+endif
+
+AOBJS	= $(ASRCS:.S=$(OBJEXT))
 COBJS	= $(CSRCS:.c=$(OBJEXT))
 
 SRCS	= $(ASRCS) $(CSRCS)
diff --git a/mm/mm_gran.h b/mm/mm_gran.h
index 6f5f890ed55..d8a334e2985 100644
--- a/mm/mm_gran.h
+++ b/mm/mm_gran.h
@@ -42,17 +42,41 @@
 
 #include <nuttx/config.h>
 
+#include <stdint.h>
+
 #include <nuttx/gran.h>
 
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Sizes of things */
+
 #define SIZEOF_GAT(n) \
   ((n + 31) >> 5)
 #define SIZEOF_GRAN_S(n) \
   (sizeof(struct gran_s) + sizeof(uint32_t) * (SIZEOF_GAT(n) - 1))
 
+/* Debug */
+
+#ifdef CONFIG_CPP_HAVE_VARARGS
+#  ifdef CONFIG_DEBUG_GRAM
+#    define gramdbg(format, arg...)    dbg(format, ##arg)
+#    define gramvdbg(format, arg...)   vdbg(format, ##arg)
+#  else
+#    define gramdbg(format, arg...)    mdbg(format, ##arg)
+#    define gramvdbg(format, arg...)   mvdbg(format, ##arg)
+#  endif
+#else
+#  ifdef CONFIG_DEBUG_GRAM
+#    define gramdbg                    dbg
+#    define gramvdbg                   vdbg
+#  else
+#    define gramdbg                    (void)
+#    define gramvdbg                   (void)
+#  endif
+#endif
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -64,7 +88,7 @@ struct gran_s
   uint8_t    log2gran;  /* Log base 2 of the size of one granule */
   uint16_t   ngranules; /* The total number of (aligned) granules in the heap */
   uintptr_t  heapstart; /* The aligned start of the granule heap */
-  uint32_t   gat[i];    /* Start of the granule allocation table */
+  uint32_t   gat[1];    /* Start of the granule allocation table */
 };
 
 /****************************************************************************
diff --git a/mm/mm_granalloc.c b/mm/mm_granalloc.c
index f94f447e315..a8802a6c511 100644
--- a/mm/mm_granalloc.c
+++ b/mm/mm_granalloc.c
@@ -39,8 +39,14 @@
 
 #include <nuttx/config.h>
 
+#include <assert.h>
+
 #include <nuttx/gran.h>
 
+#include "mm_gran.h"
+
+#ifdef CONFIG_GRAN
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -61,7 +67,7 @@
  *
  ****************************************************************************/
 
-static inline FAR void *gran_mark_allocated(FAR struct gran_s *priv, uintptr_t alloc, unsigned int ngranules)
+static inline void gran_mark_allocated(FAR struct gran_s *priv, uintptr_t alloc, unsigned int ngranules)
 {
   unsigned int granno;
   unsigned int gatidx;
@@ -128,13 +134,13 @@ static inline FAR void *gran_common_alloc(FAR struct gran_s *priv, size_t size)
   int           i;
   int           j;
 
-  DEBUGASSERT(priv);
+  DEBUGASSERT(priv && size <= 32 * (1 << priv->log2gran));
   if (priv && size > 0)
     {
       /* How many contiguous granules we we need to find? */
 
-      tmpmask   = (1 << log2gran) - 1;
-      ngranules = (size + tmpmask) >> log2gran;
+      tmpmask   = (1 << priv->log2gran) - 1;
+      ngranules = (size + tmpmask) >> priv->log2gran;
 
       /* Then create mask for that number of granules */
 
@@ -188,11 +194,11 @@ static inline FAR void *gran_common_alloc(FAR struct gran_s *priv, size_t size)
                */
 
               curr >>= 1;
-              if (next & 1)
+              if ((next & 1) != 0)
                 {
                   curr |= 0x80000000;
                 }
-              next >> 1;
+              next >>= 1;
 
               /* Increment the next candidate allocation address */
 
@@ -239,3 +245,5 @@ FAR void *gran_alloc(GRAN_HANDLE handle, size_t size)
   return gran_common_alloc((FAR struct gran_s *)handle, size);
 }
 #endif
+
+#endif /* CONFIG_GRAN */
diff --git a/mm/mm_granfree.c b/mm/mm_granfree.c
index 4679ae62b43..e359cded8c8 100644
--- a/mm/mm_granfree.c
+++ b/mm/mm_granfree.c
@@ -39,8 +39,14 @@
 
 #include <nuttx/config.h>
 
+#include <assert.h>
+
 #include <nuttx/gran.h>
 
+#include "mm_gran.h"
+
+#ifdef CONFIG_GRAN
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -66,18 +72,29 @@ static inline void gran_common_free(FAR struct gran_s *priv,
   unsigned int granno;
   unsigned int gatidx;
   unsigned int gatbit;
+  unsigned int granmask;
+  unsigned int ngranules;
   unsigned int avail;
-  uint32_t mask;
+  uint32_t gatmask;
 
-  /* Determine the granule number of the allocation */
+  DEBUGASSERT(priv && memory && size <= 32 * (1 << priv->log2gran));
 
-  granno = (alloc - priv->heapstart) >> priv->log2gran;
+  /* Determine the granule number of the first granule in the allocation */
 
-  /* Determine the GAT table index associated with the allocation */
+  granno = ((uintptr_t)memory - priv->heapstart) >> priv->log2gran;
+
+  /* Determine the GAT table index and bit number associated with the
+   * allocation.
+   */
 
   gatidx = granno >> 5;
   gatbit = granno & 31;
 
+  /* Determine the number of granules in the allocation */
+
+  granmask =  (1 << priv->log2gran) - 1;
+  ngranules = (size + granmask) >> priv->log2gran;
+
   /* Clear bits in the first GAT entry */
 
   avail = 32 - gatbit;
@@ -91,15 +108,15 @@ static inline void gran_common_free(FAR struct gran_s *priv,
 
   else
     {
-      mask = 0xffffffff >> (32 - ngranules);
-      priv->gat[gatidx] &= ~(mask << gatbit);
+      gatmask = 0xffffffff >> (32 - ngranules);
+      priv->gat[gatidx] &= ~(gatmask << gatbit);
       return;
     }
 
   /* Clear bits in the second GAT entry */
 
-  mask = 0xffffffff >> (32 - ngranules);
-  priv->gat[gatidx+1] &= ~(mask << gatbit);
+  gatmask = 0xffffffff >> (32 - ngranules);
+  priv->gat[gatidx+1] &= ~(gatmask << gatbit);
 }
 
 /****************************************************************************
@@ -132,3 +149,5 @@ void gran_free(GRAN_HANDLE handle, FAR void *memory, size_t size)
   return gran_common_free((FAR struct gran_s *)handle, memory, size);
 }
 #endif
+
+#endif /* CONFIG_GRAN */
diff --git a/mm/mm_graninit.c b/mm/mm_graninit.c
index 99b499155f9..46b5f5ff143 100644
--- a/mm/mm_graninit.c
+++ b/mm/mm_graninit.c
@@ -39,8 +39,14 @@
 
 #include <nuttx/config.h>
 
+#include <stdlib.h>
+
 #include <nuttx/gran.h>
 
+#include "mm_gran.h"
+
+#ifdef CONFIG_GRAN
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -108,7 +114,7 @@ static inline FAR struct gran_s *gran_common_initialize(FAR void *heapstart,
 
       priv->log2gran  = log2gran;
       priv->ngranules = ngranules;
-      priv->heapstart = alignedstart
+      priv->heapstart = alignedstart;
     }
 
   return priv;
@@ -161,3 +167,6 @@ GRAN_HANDLE gran_initialize(FAR void *heapstart, size_t heapsize, uint8_t log2gr
 }
 #endif
 
+#endif /* CONFIG_GRAN */
+
+